Which year trucks have the 4 hole heater access plate???

[par4tom]

I am in the process of installing a Vintage Air system, and just got off the phone with Vintage Air on a problem I am having with the heater access plate. The one I have from them has three mounting holes yet my 1961 truck requires a bigger plate with 4 holes.

The guy I spoke to, swore up and down that all of the 1960 to 1966 trucks use the same three hole plates and that I'm losing my mind. No sense arguing with him at this point...my fiance says I'm losing my mind too!!!

Here is the problem and I'm hoping you can help me out...I don't know which year trucks actually use the 4 hole plates like mine and which use the 3 hole plates that are smaller.

Can some of you gentleman help me out and tell me what year trucks actually used the 4 holes and which use the 3 holes...I'd like to communicate this back to Vintage Air.

Here is the photo of my 61 with the 4 hole plate...
tom